1. Field of the Invention
This invention concerns synthetic pharmaceutical chemistry, and provides a new solvate used in a process for purifying syn-(2-aminothiazol-4-yl)(methoxyimino) acetic acid. A bis-dimethylacetamide solvate of the acetic acid is formed and precipitated in excellent purity and yield.
2. State of the Art
The thiazolyl acetic acid which is purified by the present process is a known compound used as an intermediate in preparing a large class of cephalosporin pharmaceuticals, the acyl side chain of which is formed from the thiazolyl acetic acid. Numerous patents and publications have appeared. For example, U.S. Pat. No. 4,152,433 of Fujisawa Co. and U.S. Pat. No. 4,098,888 of Takeda Chemical Industries show the synthesis of various cephalosporin compounds making use of the thiazolylacetic acid as an intermediate. Often the amino group of the substituted acetic acid is blocked by a group such as trityl or the like, and the acid is usually converted into an active form such as the acid chloride or the like for use as an acylating agent.
The formation of solvates is known to be a highly individualistic effect. The ability of a given compound to form a solvate is not predictable, so far as applicant knows, and to his knowledge and belief nothing in the literature indicates that the thiazolyl acetic acid which is the subject of this invention can form a solvate with dimethylacetamide, or with any solvent.